The noise on the clean channel when the reverb is in engaged is really bugging me. Is this something that is common on all RA100s? I've swapped all the pre-amp tubes, power tubes, not the PI though. Can be heard when there is no input and master is off. Really annoying to have a high dollar amp (or any amp) not be dead silent. My MKV and Roadster don't give me this issue. Is this a design flaw or just my amp?
I don't have an issue with the reverb on my RA-100. You swapped power tubes for an issue that you narrowed down to being related to the spring reverb tank of the amp? Why would you do that?
If you swapped the tube for the reverb, the next thing I would to would be to check the connections of the wires that connect the tank to the amp. Pull them out and reseat them into their respective sockets. Turn on the amp and give it a go.
If you are having noise in your amp that is being further amplified by turning up your reverb, the problem isn't the reverb tank. Reverb tanks and reverb units in amps take the signal and any noise (good or bad) from the preamp and send it to the power tubes for amplification. If you hear a noise that gets louder with the reverb knob turned up, with nothing at all plugged in the amp, I would think the noise would be emanating from a faulty preamp tube. If the sound is happening in all channels, it is safe to say you have a bad PI tube (V-7). I had a noisy V-7 tube and swapped it out for a good tube and it solved my noise issues. Try one of Mesa's SPAX7s for that slot. They are quieter and ideally used for V-1 slots, but can make a world of difference in the PI due to their quiet nature.
Don't forget that if you swapped around tubes, you may have overlooked that the V-3 slot MUST HAVE A 12-AT7 tube and NOT the AX7 tube in it. That is the effect loop tube. With the Royal Atlantic, the effects loop is bypassed when there isn't an instrument cable hooked up. Therefore, your elusive noise issue probably isn't originating from the V-3 slot. Still though, I'd be sure that you have the right tube in V-3.